This mind-boggling optical illusion has gone viral for tricking your eyes

Photo / Twitter

Photo / Twitter

Ah, we sure do love a good optical illusion - and this latest photo has left our minds truly boggled.

The snap - which has gone viral after being shared to Reddit and Twitter - features a group of school girls smiling while getting photographed with a tortoise, and at first glance, it looks like a regular colour photo.

But can you see what’s weird about it?

Photo / Twitter

It turns out that the photo is actually black and white and that the colour that we are seeing is actually just gridded lines.

Seriously, how weird is that?!

Essentially what's happening is that your brain is filling in the blanks and make the whole image seem as though it is a full-colour photo, even though it is not.

Mind blown!